Where the propellant went: locating deep-space maneuver exhaust from navigation-arc discontinuities

Adrien Normier · 2026 · dataset and method © Adrien Normier · derived data layer shipped in the SolarSystemRegistry ("exhaust")

Idea

Every interplanetary trajectory correction throws propellant overboard. The gas does not vanish: each puff leaves the spacecraft at the engine's exhaust velocity, picks up its own heliocentric orbit, and keeps flying it — humanity's least visible footprint in deep space. This note derives WHERE those puffs are, from public navigation products alone.

Method

The registry's trajectory layer carries piecewise osculating elements from JPL Horizons — the missions' own navigation solutions, sampled per arc. Two consecutive arcs evaluated at their common boundary epoch t agree in position but not in velocity; the discontinuity

Δv⃗ = v⃗after(t) − v⃗before(t)

is the integrated maneuver activity around that boundary. Where |Δv| clears a 10 m/s detection floor (orbit-determination noise and small perturbation residue stay below it), a maneuver is declared. Momentum conservation places the gas: it leaves opposite the thrust direction at the exhaust speed,

v⃗gas = v⃗before − ve·Δv⃗/|Δv|,   ve ≈ 3.1 km/s (storable bipropellant class)

and the expelled mass follows Tsiolkovsky with the catalogued spacecraft mass m as the post-burn proxy:

mp = m·(e|Δv|/ve − 1)

Each detected puff becomes a registry node (origin ARTIFICIAL, provenance MODELLED) with the burn-epoch heliocentric state, and drifts on its own orbit thereafter. The visualization shows them appearing at their burn dates and receding from their ships.

Declared limits

Yearly arc sampling AGGREGATES all Δv near a boundary — including gravitational perturbation residue between fits — so each puff is an upper-bound PROXY for the boundary's maneuvers, not a reconstructed burn list. Burns between samples of the same arc are invisible. ve is a class median, not per-engine; ion missions (Dawn's 10+ km/s of slow thrust) violate the impulsive assumption and their puffs read as smeared aggregates. Finer SPICE kernels (queued) will sharpen boundaries toward real burn epochs.

Data

Current bake: 106 puffs from 226 arc boundaries across the Horizons-served missions, all carrying Tsiolkovsky propellant mass. Browse them in the database or search kind:exhaust-plume in the simulation.

License & citation

Dataset and method © Adrien Normier, under SSR-GPL v2.0 (public-interest use free, attribution “SolarSystemRegistry.org — Adrien Normier”). Underlying osculating arcs: NASA/JPL Horizons (public domain — cite JPL Horizons). Cite this page and SolarSystemRegistry.org.